MLE-26538 Fixing reference to Java 11 in docs

[rjrudin]

No description provided.

[github-actions]

Copyright Validation Results
Total: 5 | Passed: 0 | Failed: 0 | Skipped: 5 | at: 2026-01-23 18:18:58 UTC | commit: 4fd0add

⏭️ Skipped (Excluded) Files

• .copyrightconfig
• docs/api.md
• docs/import/embedder/custom-integration.md
• docs/index.md
• flux-custom-splitter-example/README.md

✅ All files have valid copyright headers!

[Copilot]

Pull request overview

This PR updates Java version references in documentation to reflect current system requirements, replacing Java 11 with Java 17 and Java 21.

Changes:

• Updated system requirements to specify Java 17 or Java 21 as supported versions
• Removed outdated note about Java 21 testing status
• Updated developer prerequisites to require Java 17 or Java 21

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
flux-custom-splitter-example/README.md	Updated Java version requirement from "11 or higher" to "17 or Java 21"
docs/index.md	Updated system requirements and removed outdated Java 21 testing note
docs/import/embedder/custom-integration.md	Updated developer prerequisite from "Java 11 or higher" to "Java 17 or Java 21"

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[Copilot]

The phrasing 'using Java 17 or Java 21' creates an inconsistency with the other documentation files which use 'Java 17 or higher'. Consider whether this should be 'Java 17 or higher' to allow for future Java versions, or if the restriction to only Java 17 and 21 is intentional and should be consistently documented.

Suggested change

	perform the following steps, using Java 17 or Java 21:
	perform the following steps, using Java 17 or higher: